Hard disk drives are used in almost all computer system operations. In fact, most computing systems are not operational without some type of hard disk drive to store the most basic computing information such as the boot operation, the operating system, the applications, and the like. In general, the hard disk drive is a device which may or may not be removable, but without which the computing system will generally not operate.
The basic hard disk drive model was established approximately 50 years ago and resembles a phonograph. That is, the hard drive model includes a storage disk or hard disk that spins at a standard rotational speed. An actuator arm with a suspended slider is utilized to reach out over the disk. The arm carries an assembly that includes a slider, a suspension for the slider and in the case of the load/unload drive, a nose portion for directly contacting the holding ramp during the unload cycle. The slider also includes a head assembly including a magnetic read/write transducer or head for reading/writing information to or from a location on the disk. The complete assembly, e.g., the suspension and slider, is called a head gimbal assembly (HGA).
In operation, the hard disk is rotated at a set speed via a spindle motor assembly having a central drive hub. Additionally, there are tracks evenly spaced at known intervals across the disk. When a request for a read of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head reads the information from the disk. In the same manner, when a request for a write of a specific portion or track is received, the hard disk aligns the head, via the arm, over the specific track location and the head writes the information to the disk.
Recently some disk drives are being filled with low-density gases other than air (i.e., helium) to enhance their performance. The lower density gas can reduce the aerodynamic drag between the disks and their read/write heads. This reduced drag can, in turn, reduce arm and suspension flutter and actuator buffeting. This reduced drag can also result in a reduction in power requirements for the spindle motor. The lower density gas also is more effective than air for conducting away heat generated during operation of the disk drive.
Unfortunately, in spite of the advantages associated with the low-density gas fill, these gas filled disk drives have associated problems that have impacted their commercial success. These problems are associated with a leaking of the gas from the disk drives over time. Data loss can occur if the gas fill becomes too low.
Additionally, during the manufacture of the low-density gas filled disk drives, the series of tests that are performed on the drives for quality assurance are frequently failing due to leakage of the helium. These tests are performed on disks that have been filled with helium and semi-sealed. These tests may take a period of days to complete, and if a failure occurs many hours into the test and the failure is due to loss of helium, the disk must be refilled and the test restarted, thereby resulting in a significant time loss.